Apparatus for forming can tops and lids



Dec. 31, 1946. 1 w, sTURDY 2,413,591

APPARATUS FOR FORMING CAN TOPS AND LID S Filed April 7, 1944 2 Sheets-Sheet l j'nvenTor 6; L150. .SiurcYy Dec. 31, 1946.

L. W. STURDY APPARATUS FOR FORMING CAN TOPS AND LIDS Filed April 7. 1944 2 Sheets-Sheet 2 :iTIUCTIT r L Z1}- Sill-rd a WXM verted into the lid blanking the ring lfateated Dec; 31, 1945 ffauasai arr-mews Fon mmeciums 7-, mum s x w. Sturdy, London, omen Application April 1. 1944, No. 52am 1 i 40lalms. (cans-.42)

in particular a the a ring anda Myinvention a minuiacture of a can top havin The ordinary can oncontainer or the detachable closure type-hasa-topiormed by a ring whichseats thelid g Previous to my invention, so turns 1 am aware, it was the usual practice to form the ring-like top bya punch and die in a press and to use a separate punch and die for forming the lid. The central piercing from the as a slug, and a common manner of disposing of this slug wasrtovpush it upwardly out of 'the die, or to force it downwardly therethrough. V'The paramountiobject' of my invention is to ring was discarded die showing the.

provide a punch anddie for, forming a canring and lid in a single operation, the lid being adapted for a can voi! a smaller size than that for which theringismade, 4

A further object is toprovide a combination punch and die which will produce a'ring and lid of'the nature "specified in a single press operation in which the central piercing of the ring is coninorder to utilize this slug and thus eiiectasubstantial saving in material and cost of manufacture.

A still further object is to produce a punch and die which will form the ring and the lid entirely automatically and in a manner to substantially eliminate all hazard to the punch and die.

A distinctive feature of the invention is that my method of manufacture produces the two parts for cans in one operation on an ordinary press in charge of a single operator. The sheet metal stock from which the two parts are simultaneously madeis of the same size as customarily required for a ring.

A distinctive feature of the punch and die is that they have inner and outer cutting edges for and intervening forming surfaces which draw the blankinwardly from said cutting surfaces so that the formed ring may be readily pushedupwardly out of the die for ejection from the press. Additionally there is provided suitable forming. surfaces centrally of the said inner cutting edges of the punch and die, which form the central piercing into the lid and reduce its diameter withthe result that it likewise can be readily pushed upwardly out of the die for election from the press.

In actualpractice my invention has been found to be highly practical andeoonomical in the manufacture of rings. andlids of cans.

The selected embodiment of the invention is illustrated in the accompanying drawings, in which:

Q Fig. 1 is a central sectionalview of the punch. 2is a central sectional view of the die used in conjunction with the punch.

' Fig. 3 is a sectionalview of the inverted rin and the lid formedby the punch and die. I Fig. is a central section of the punch and H I first step of cutting the ring and lid blanks from the stock in the descent of the punch. h

Fig. 5 is a similarviewto Fig. 4, but shows the next step of forming the blanks into the ring and the lid. I V Fig. 6 is a fragmentary perspective view of the ring. and Fig. 7 is a similar view of the lid.

Like numerals of reference indicate similar parts throughout the drawings of the invention. In the can industry it is common to make cans and the like with closures that are secured by a friction iit between the closure itself and the top or the can. Such a top usually has a downturned flange l0 forming a mouth receptive to the closure. Before the top is applied to the cylindrical body of the can it is common to provide it with anannular loop or channel H, from which extends an attachment flange l2, as will be well understood in the a g The top constitutes a ring, and the closure is a lid which commonly has a central depression ll forfltting into the mouth of the top, and a radial flange It. It is not an object of my invention to change the form of the ring and the 11 ,but to provide a combination punch and die,. which in one stroke of a press will form a top for a can of a certain size and a lid tor a can of asmaller size, using the disc that is cut from the centre of the top. Such a top and lid are illustrated in Figs. 3, 6 and 'l, and shown inverted as this is the position in which they are formed by the punch and die. A standard press is used preferably having its operating axis inclined about forty-five degrees to the vertical.

The punch, generally denoted at I5, is fitted in the crosshead of the press as by means of the element II, and the die is mountedupon the bed by'means of a bolster II. The punch comprises the external cutting edge It and the internal cutting edge It. the outer annular forming ring 10,

-the inner annular forming ring 1!, and the knock-out member 22.

The die comprises the cutting edges 23 and 24 which correspond respectively to the cutting edges i8 and I9 aforesaid. The die also includes the outer annular forming ring 25, the central forming plug 20 and the knock-out rin s 21 and.

The knock-out member I! of the punch is backed by a spring 20 and guided by the element to in its receding movement. The knock-out members H and it are separately backed by springs 3i and 32, and shouldered in well-known manner to limit their upward movements.

In the working stroke of the press,. the first step of the operation. Fig. 4, consists in cutting vfrom the sheet stock 33. by means ofthe cutting edges i8, i0, 23 and 24, the blanks from which the top A and the lid B are to be formed.- The periphery l2 0! the blank for thetop A is clamped draw in the external diameter of the blank and also the internal diameter thereof, which assures of its being free of the cuttingedges of the die in its final form. coincidentally with the forming of said loop the flange I2 is formed, and the inner edge portion of the blank is turned up by its being forced downwardly over a shoulder I6 by the inner edge 31 of the forming ring 2. which is spaced from the forming ring 24 to clear the shoulder at. The bending of this inner edge portion forms the flange N at the mouth of the top. It will now be understood that the top A is completely formed in thesecond step by means of the forming surfaces referred to, as the punch of cutting the blanks.

During the second step, the periphery of the blank for the lid B is clamped between the annular forming member 2i and the knock-out ring 28, and forced downwardly over the central forming member 28 to form the flange II. The drawing of this flange reduces the diameter of this blank with the result that it is clear of the cutting edge 24 of the die and may be ejected without any tendency to stick in the die and damage the same.

The top A and the lid B are ejected by the knock-out devices 27 and 28 in the inverted disposition in which each is formed. There is no waste of material and the formed parts are free to drop freely from the press when ejected from the die. There is obviously a considerable saving both-in time and labour in producing the two articles in a single operation.

Whereas the invention has been described and illustrated as applicable for the production of a descends further with respect to the first step single ring in conjunction with a lid, it will be manifest that it could be used for the manufacture of a multiple of rings and a lid at the same time by duplication of the ring-making parts on the punch and die. v

Having discios the selected form of the invention it will b manifest that such changes and variations may be resorted to as come within the spirit and scope of the appended claims.

I claim:

1. A punch and die for forming in one operation a top for a can. and a lid for another can of a difierent size, comprising means for cutting a blank from suitable stock, means for clamping the rim of said blank,- means for forming an annular loop in said blank inside of said rim and an annular dance on said blank inside oi said loop as said clamping means retards the movement inwardly of the material, means for cutting out a disc from said blank; including a forming ring in the die having an inner annular cutting edge, means for clamping the rim of said disc. and means for fcrniing'a flange on said disc characterized in that it includes a central cylindrical forming member in the die, having a peripheral drawing shoulder of a less diameter than said cutting edge which provides a space receptive to an annular member on the punch having an inner drawing shoulder for co-acting with said drawing shmilder to vflange the disc, said space, containing a clamping ring operative to elect the disc-upwardly from the die in the return stroke of the press. 4

2. A punch and die for forming sheet material into a can ring and a lid, the punch comprising an outer annular cutting ring, an inner annular forming ring-spaced therefrom, and a central yieldable knock-cutnmemberhaving a clamping face, the outer edge-of said outer ring having a cutting edge-and the inner edge thereof having a shoulder formed by anadiacent recessin the-lower surface and spaced from said cutting. edge, the outer edge of said inner ring having a cutting edge and having a drawing edge, said die comprising-mower annular cutting ring, an innerannular jiorming ring spaced therefrom, a-centra'l'member spaced from the innerring; 'andl'yieldable knock-out rings in the spaces provided between the outer ring andthe between the inner ring and the central member, the inner edge of the outer ring having-a cutting edge co-acting with the cutting edge on. the outer ring of the punch, the inner edge of the inner ring having a cutting edge co-acting with the cutting edgeon the inner ring of the punch and that ring having a shoulder'at its outer edge formed byan adjacent recess-to co-act with the shoulder and recess on the outer ring 'of the punch to provide a loop and a flange on the can ring cut from the material, the central forming member having anouter shoulder over which the disc cut from the can ring is drawn by the drawing edge of the inner ring on the punch to form a lid.

3. A punch anddieas defined in claim 2. in which in the drawing of the disc the central portion thereof is clamped by the knock-out member in the punch, and in which the edge portion of the disc is'clamped by the knockout member located between the inner ring and the central member of the die.

4. A punch and die of the class described comprising means for cutting a blank from suitable stock and for performing forming and cutting operations thereon inside its rim portion while said rim portion is yieldably clamped to retard the movement inwardly of the material, said.

- means including a forming ring in the die having an inner annular cutting edge, the improvement including a ring in the punch inwardly of said ring having an outer annular cutting edge for co-acti-ng with said cutting edge thereof to sever a disc from the blank and having an inner drawing shoulder, a central forming member in the die having a peripheral forming shoulder of a less diameter than said cutting edge of the first mentioned forming ring inner drawing shoulder, and a clamping ring in said space operative to upwardly eject said disc. I

' LEONARD W. STURDY. 

